fix(array): fix edge case on single boolean index (#28)

hanxiao · web-flow · commit 79ad2362df1e · 2022-01-11T12:26:25.000+01:00
diff --git a/docarray/array/document.py b/docarray/array/document.py
@@ -129,7 +129,7 @@ def __getitem__(
     def __getitem__(
         self, index: 'DocumentArrayIndexType'
     ) -> Union['Document', 'DocumentArray']:
-        if isinstance(index, (int, np.generic)):
+        if isinstance(index, (int, np.generic)) and not isinstance(index, bool):
             return self._data[int(index)]
         elif isinstance(index, str):
             if index.startswith('@'):
diff --git a/docs/fundamentals/documentarray/access-elements.md b/docs/fundamentals/documentarray/access-elements.md
@@ -120,6 +120,8 @@ print(da)
 <DocumentArray (length=50) at 4513619088>
 ```
 
+Note that if the length of the boolean mask is smaller than the length of a DocumentArray, then the remaining part is padded to `False`. 
+
 (path-string)=
 ## Index by nested structure
 
diff --git a/tests/unit/array/test_advance_indexing.py b/tests/unit/array/test_advance_indexing.py
@@ -219,3 +219,15 @@ def test_advance_selector_mixed():
 
     assert len(da[:, ('id', 'embedding', 'matches')]) == 3
     assert len(da[:, ('id', 'embedding', 'matches')][0]) == 10
+
+
+def test_single_boolean_and_padding():
+    from docarray import DocumentArray
+
+    da = DocumentArray.empty(3)
+
+    with pytest.raises(IndexError):
+        da[True]
+
+    assert len(da[True, False]) == 1
+    assert len(da[False, False]) == 0
